Gases, which do not obey ideal gas equation under all the conditions of temperature and pressure are called real gases. For real gases, the ratio of PV/RT will be either greater than 1 or less than 1. Real gases show deviation from ideal gas behaviour at higher pressures and lower temperatures. The intermolecular attractive forces are not negligible in real gases. In real gases, the actual volume of the molecules cannot be neglected as compared to the total volume of the container.
